Scroll compressors have become widely utilized in many refrigerant compression applications. Scroll compressors are relatively efficient, and are being utilized in more and more applications. In a typical scroll compressor, the compression chambers are defined by two generally spiral wraps. The spiral wraps are formed on individual scroll members, and extend from a base plate. The spiral wraps interfit to define compression chambers. One of the spiral wraps is driven to orbit relative to the other, and the size of the compression chambers changes to compress the entrapped refrigerant.
As the compression chamber nears the end of its cycle, the entrapped gas is exposed to a discharge port. The entrapped gas leaves the discharge port and moves through a check valve to a discharge plenum. The discharge check valve is typically opened during operation of the scroll compressor. The check valve closes the discharge port and desirably prevents backflow once the compressor is stopped.
In scroll compressors, there is a phenomenon known as reverse rotation. This occurs when compressed gas moves back through the discharge port and into the compression chamber to drive the scroll compressor wraps relative to each other in a reverse direction at shutdown of the compressor. This is undesirable, and results in unwanted noise and potential harm to the compressor components.
One method of minimizing the amount of reverse rotation is to minimize the volume of compressed gas which will move between the scroll wraps at shutdown. The present invention provides a discharge valve that is designed to be fast acting in closing the discharge port upon shutdown of the compressor.
A discharge valve, according to the principles of the present invention, includes a valve seat having a seat surface facing downstream of a discharge passage of the scroll compressor. A valve member is provided having a body portion for engaging the seat surface of the valve seat for closing the discharge passage. The valve member includes a guide portion extending axially from the body portion. A retainer is slidably engaged with the guide portion of the valve member and includes at least one passage communicating with a space between the valve member and the retainer. According to one aspect of the present invention, the guide portion of the valve member includes at least one notch portion in communication with the space between the valve member and the retainer. During operation of the scroll compressor, the valve member is lifted away from the valve seat and slidably moves relative to the retainer to an open position. At shutdown, the discharge pressure in the discharge chamber acts upon the valve member through the at least one passage communicating with the space between the valve member and the retainer to cause the valve member to move to its closed position. The notched portions in the guide portion of the valve member serve a dampening effect with regard to the motion of the valve member between the open and closed positions.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.